Tunable semiconductor component provided with a current barrier

ABSTRACT

Semiconductor component or device is provided which includes a current barrier element and for which the impedance may be tuned (i.e. modified, changed, etc.) using a focused heating source.

The present invention relates to the field of semiconductor componentsor devices. and is directed to semiconductor components or devices theimpedance of which may be tuned (i.e. modified, changed, etc.) using afocused heating source.

The present invention is in particular directed to semiconductorcomponents or devices the electrical structure of which may be modified,for example, by the use of a laser, for the creation of conductive linksand pathways where none existed before.

The modification of the impedance of a (integrated) semiconductor deviceor component through the use of lasers is known in the art. Such methodsare sometimes referred to as laser trimming of (integrated)semiconductor devices.

It is known for example to (finely) tune the impedance of semiconductorcomponents or devices, by modifying the dopant profile of a region oflow dopant concentration (i.e. increasing the dopant concentration) bydiffusion of dopants from adjacent regions of higher dopantconcentration through the melting action of a focused heating source;the heating source may take any form whatsoever keeping in mind itspurpose as described herein; the heating source may for example be ableto provide an energy beam such as, for example, a laser beam.

It is in particular known to iteratively selectively tune the impedanceof (integrated) semiconductor devices or components, by modifying thedopant profile of a region; see for example U.S. Pat. No. 6,329,272, aswell as, U.S. Pat. No. 6,890,802; the entire contents of each of thesepatents is incorporated herein by reference.

The above mentioned U.S. Pat. No. 6,890,802, describes a semiconductordevice or component wherein a base (or main) conductive path (as laiddown) of the device or component has an initial (i.e. non-infinite)impedance (e.g. non-infinite resistance) and has a configuration wherebythe main conductive path is capable of being trimmed or tuned bydecreasing such impedance, e.g. by a laser trimming technique such asdescribed in this patent.

It is known that an integrated semiconductor device may comprise anumber of components. Included among these may be areas which may bedoped with dopants, such as for example, n type or p type dopants. Thedopant concentration of various areas of a device may vary according totheir use and application, and there may be, for example, areas of agiven dopant concentration, and adjacent thereto there may be areas ofhigher or lower dopant concentration. It is known that there maytherefore be a pair of first areas of a predetermined or selected dopantconcentration, and an adjacent intermediate second area of a (relative)lower dopant concentration. As may be understood, the difference in thedopant concentration between areas may be sufficient such that thephysical and electrical properties of each of the areas may bedifferent, i.e. for example, under predetermined operating conditionsone may conduct electrical current, while the other may not, or theirrelative capability to conduct electrical current may be different.

Thus U.S. Pat. No. 6,890,802, generally describes an impedance tunablesemiconductor component or device which comprises a first conductiveregion and a second region contiguous with the first region; theseregions may be subjected to heating/solidification bridging cycle(s),i.e. for laser trimming. The first conductive region is described asdefining a laid down base conductive path and as comprising a first linkmember and a second link member disposed in juxtaposition such that thefirst and second link members are separated by a gap region defined bythe second region. The first conductive region is a doped region havinga heat modifiable dopant profile. The second region is described asbeing a doped region having a dopant profile rendering said secondregion non-conductive relative to said first region. The second regionis also described as having a heat modifiable dopant profile, at leastwith respect to the gap region. As described in U.S. Pat. No. 6,890,802a focused heating source, such as for example a laser, may be used tocreate or form, a discrete conductive bridge between the first linkmember and the second link member across the gap region; in other wordsby the application of a melting/solidification cycle(s), a secondaryconductive path may be formed which electrically connects the first linkmember and the second link member across the gap region.

A first conductive region may be laid down onto a second region by any(known) type of semiconductor making masking technique; i.e. any knownprocess in which unmasked areas of a substrate (e.g. silicon) exposedfor example by (known) optical lithographic techniques are bombardedwith one or more dopants (i.e. dopants as described herein) to alter theway the silicon conducts electricity in those areas. However, when afirst conductive region is laid down onto a second region by (known)lithographic type masking techniques. the masking procedure may, if notrigorously carried out, give rise to an undesirable imperfect result;such imperfection may be due to inadequate thickness of the mask, to thecomposition of the mask, to the doping duration, etc. Due to theimperfect masking of the portion of the second region intended to be thegap region, the second region defining the gap region may be associatedwith a hybrid layer (or hybrid region(s)) having an effective dopantcomposition similar to that of the above mentioned opposed link members.Such a hybrid layer (or hubrid region(s)) may shorten the effectivedistance between the above mentioned opposed link members or even becontiguous with (i.e. connect) the opposed link members. The hybridlayer (or hybrid region(s)) may for example be relatively thin ascompared to the opposed link members. Nevertheless any such hybrid layer(or hybrid region(s)) if present may be such that under (predetermined)operating conditions the hybrid layer (or hybrid region(s)) may allow orfacilitate undesired leakage of current across the gap region. Thus,depending on the masking technique used, the mask thickness, the maskingmaterial as well as the materials used for the first conductive regionand the second region and/or the distance between the first link memberand the second link member, (direct) current leakage may occur acrossthe gap region even though the gap region is composed of a material(s)believed to be of a non conductive type, i.e. current may directly crossthe gap region in areas not provided with a secondary conductive path.Even, if the masking technique is relatively rigorous such that a hybridlayer (or hybrid region(s)) is for all intents and purposes non-existent(or inconsequential), nevertheless due to the materials used for thefirst conductive region and the second region, the distance between thefirst link member and the second link member, the operating parameters(i. e. voltages used), etc., some (direct) current leakage may yet occuracross the gap region. The current leakage may be more pronounced as thedistance between the first link member and the second link memberreaches very small values such as for example 5 microns or less (e.g.0.1 to 5 microns) i.e. the close proximity of the first link member andthe second link member may favour direct current leakage across theacross the gap region. In other words, the manipulation and control ofthe impedance of a device or component thereof by the creation ofconductive bridge(s) such as described for example in U.S. Pat. No.6,890,802, may be complicated by the leakage of current across the gapregion between the first link member and the second link member (i.e.uncontrolled or direct current leakage).

It would be advantageous to have means that may offset (i.e. balance,counteract, or compensate for) the possibility of an above mentionedelectrical current leakage. It would in particular be advantageous tohave a means whereby the gap region may be interrupted by a currentbarrier region or mask for impeding or arresting the possibility ofleakage of current directly across the gap region.

It would be advantageous to have a semiconductor device or componentwhich may be subjected to the above mentioned bridging cycle(s) andwhich may be provided with (relatively simple) means for providing aresistance (i.e. impedance) barrier or current barrier or mask betweenthe first link member and the second link member in order to offset(i.e. inhibit) the possibility of leakage of current across the gapregion (i.e. offset uncontrolled or direct current leakage).

Thus, the present invention generally relates to a current mask regionor member configured and disposed to interrupt the above mentioned gapregion for offsetting (i.e. inhibiting) the possibility of leakage ofcurrent (i.e. inhibiting uncontrolled or direct leakage of current)across the gap region between the first link member and the second linkmember. The current mask region or member may be spaced apart from thefirst link member and the second link member any desired, necessary orsuitable distance for offsetting the possibility of leakage of currentacross the gap region and is a doped region having a heat modifiableconductive dopant profile.

The present invention in particular provides an impedance tunablesemiconductor component, said semiconductor component comprising a firstconductive region defining a laid down base conductive path, said firstconductive region comprising a first link member and a second linkmember, said first region being a doped region having a heat modifiabledopant profile and a second region contiguous with the first region,said second region being a doped region having a dopant profilerendering said second region non-conductive relative to said firstregion, said first and second link members being disposed injuxtaposition such that said first and second link members are separatedby a gap region defined by said second region, said second region havinga heat modifiable dopant profile, at least with respect to said gapregion

characterised in that a current mask region is configured and disposedso as to interrupt said gap region between said first link member andsaid second link member for offsetting leakage of electrical currentacross the gap region between the first link member and the second linkmember, said current mask region being a doped region having a heatmodifiable conductive dopant profile.

More particularly the present invention provides an impedance tunablesemiconductor component, said semiconductor component comprising

-   -   a first conductive region, and    -   a second region    -   said first conductive region comprising a first type dopant        composition    -   said second region comprising a second type dopant composition    -   said second type dopant composition having a dopant profile        configured to render said second type dopant composition        non-conductive relative to said first type dopant composition    -   said first conductive region and said second region being        contiguous,    -   said first conductive region defining a laid down base        conductive path,    -   said first conductive region comprising a first link member and        a second link member,    -   said first and second link members being disposed in        juxtaposition such that said first and second link members are        separated by a gap region defined by said second region,    -   said first conductive region having a heat modifiable dopant        profile,    -   said second region having a heat modifiable dopant profile, at        least with respect to said gap region,    -   characterised in that said semiconductor component further        comprises a laid down current mask region disposed between and        spaced apart from said first link member and said second link        member, said current mask region having a heat modifiable dopant        profile, and wherein said current mask region comprises a third        type dopant composition different from that of said first and        second type dopant compositions such that said current mask        region interrupts said gap region for offsetting leakage of        electrical current across the gap region between the first link        member and the second link member.

In accordance with the present invention the first, second and thirdtype dopant compositions as mentioned above or first, second or thirdregions as mentioned below may each be configured such that each isselected from the group consisting of a p-type dopant composition and ann-type dopant composition, each dopant composition being configuredkeeping in mind its purpose or function as described herein.

It is understood herein that the amount of dopant to be diffused from anarea (or areas) of higher dopant concentration into an area(s) of lowerdopant concentration may need to be high enough to counter the presenceof the different type of dopant present in the lighter doped areas, suchthat current may flow through said lightly doped area.

In accordance with the present invention if, for example, a doped firstregion uses a high concentration of p-type dopant, the lighter dopedregions are to be of n-type and vice versa.

Thus for example, a first type dopant composition may be configured tobe a p-type composition of high p-type dopant concentration whereassecond and third type dopant compositions may both be n-typecompositions. The third type dopant composition may be furtherconfigured to have a high n-type dopant concentration relative to thatof the second type dopant composition but have a lower dopantconcentration relative to the dopant concentration of the first dopantcomposition. In other words the second type dopant composition maycomprise a concentration of n-type dopant which is lower than the dopantconcentration of the first and third dopant compositions. It is to beunderstood herein that a dopant composition (or region) may compriseboth p and n type dopant but the dopant character of such a dopantcomposition (or region) is determined by the dopant which is present ina preponderant or majority amount; i.e. a dopant composition whichcomprises both p and n type dopants may be nevertheless be considered asan n-type dopant composition if the majority of dopant is of the n-typedopant (and vice versa).

In accordance with the present invention a gap region or area may, forexample be interrupted by a current mask region, member or area suchthat the current mask area, member or region may be a distance, fromeither of the above mentioned link members, of 5.0 microns or less (e.g.from 0.1 to 5.0 microns) and in particular a distance of 0.8 microns orless (e.g. from 0.2 to 0.8 microns). As desired or necessary the gapregion or area as a whole may span a distance of 5.0 microns or less(e.g. or less 0.1 to 5.0 microns) between the above mentioned linkmembers.

In accordance with the present invention the current mask region ormember may be spaced apart from the first conductive region oralternative be linked (i.e. be contiguous) to a portion thereof otherthan the link members. In any case the current barrier region or memberis still not to have the same dopant profile as the first conductiveregion, i.e. the third type dopant composition of the current maskregion is not to be of the same dopant type as that of the first typedopant composition of the first conductive region. The current maskregion or member may as desired or necessary partially or entirely maskthe first link member from the second link member.

In accordance with another aspect of the present invention, it hasfurther been appreciated that circumstance may arise wherein it would beadvantageous to have a means available in situ in a semiconductor deviceor component whereby the semiconductor device or component may beconfigured to custom define by (laser) heat trimming a fractional amountof current that may flow through a predetermined electronic circuit(i.e. a trimable voltage or current divider (potentiometer) component).

Thus the present invention in a further aspect provides an impedancetuneable semiconductor component, said semiconductor componentcomprising

-   -   a first conductive region defining a first discrete laid down        base path for electrical conduction, said first region being a        doped region having a heat modifiable dopant profile.    -   a second conductive region defining a second discrete laid down        base path for electrical conduction, said second region being a        doped region having a heat modifiable dopant profile    -   and    -   a third region contiguous with the first and second regions and        being a doped region having a dopant profile rendering said        third region electrically non-conductive relative to said first        and second regions,    -   at least a potion of said second discrete laid down base path        being disposed in juxtaposition with said first discrete laid        down base path such that said first and second discrete laid        down base paths are thereby separated by a gap region defined by        said third region,    -   said third region having a heat modifiable dopant profile, at        least with respect to said gap region,    -   said first conductive region having a pair of electrical contact        means for electrically connecting the first conductive region to        two or more electrical elements,    -   said second conductive region having an electrical contact means        for electrically connecting the second conductive region to one        or more electrical elements.

In accordance with the present invention the first and second conductiveregions as well as the third region may have dopant profiles or dopantcompositions as described above keeping in mind their purpose.

In accordance with the present invention the second discrete laid downbase path may comprise a first element disposed transverse to a secondelement projecting from the first element, said second elementcomprising said contact means of said second conductive region, saidfirst element being disposed in juxtaposition with said first discretelaid down base path so as to be separated therefrom by said gap region.

In accordance with the present invention the second discrete laid downbase path may comprise a T-like shaped member having a head element anda tail element projecting from the head element, said tail elementcomprising said contact means of said second conductive region, saidhead element being disposed in juxtaposition with said first discretelaid down base path so as to be separated therefrom by said gap region.

In accordance with the present invention the second discrete laid downbase path may comprise an L-like shaped member having a foot element anda leg element projecting from the foot element, said foot elementcomprising said contact means of said second conductive region, saidfoot element being disposed in juxtaposition with said first discretelaid down base path so as to be separated therefrom by said gap region.

In accordance with the present invention an impedance tuneablesemiconductor component having discrete first and second laid down basepaths as described herein may further include a laid down metallicbridge element and wherein said first and second conductive regions areelectrically interconnected by said metallic bridge element, saidmetallic bridge element being severable by a focused heating source. Thepresence of such a metallic element will allow for the initial testingof the semiconductor device to see if it is functional; after suchinitial testing the metallic link element may be cut as by a suitablelaser beam etc. The metallic bridge element may be initially laid downin any suitable (known) manner.

In accordance with the present invention, impedance tuneablesemiconductor component having discrete first and second laid down basepaths as defined herein may further comprises a laid down current maskregion (as described herein) interposed in said gap region, said currentmask region having a heat modifiable dopant profile, and wherein saidcurrent mask region comprises a dopant profile different from that ofsaid first and second conductive regions such that said current maskregion interrupts said gap region for offsetting leakage of electricalcurrent across the gap region between said first and second conductiveregions. In accordance with the present invention the current maskregion may have a dopant profile or dopant composition as describedabove keeping in mind its purpose as decribed herein.

It is to be understood herein that the expression “heat modifiabledopant profile” characterizes a region or area (as the case may be) asbeing one which may, on the application of a suitable heat source, bemelted such that dopant may migrate or diffuse there through so as toalter the dopant profile thereof which may be maintained onsolidification of the melted area.

It is to be understood herein that the word “impedance” relates to bothresistance and capacitance, and that modifying the impedance of anintegrated semiconductor device is understood to comprise modifying theresistance and/or the capacitance of a semiconductor device orcomponent, as the case may be.

In accordance with the present invention it is to be understood hereinthat the expression “laid down” when used in relation to a path, region,element or the like, characterises the path, region, element or thelike, as having been initially created by a process other than lasertrimming (e.g. by (known) lithographic type masking techniques).Accordingly, the reference to a “laid down current mask region” is to beunderstood as referring to a region which has been previously created(e.g. by (known) lithographic type masking techniques) prior to any typeof tuning or trimming as discussed herein. The reference to a “laid downmetallic bridge element” is to be understood as referring to a metallicbridging member created by an suitable metal deposition technique usedin the manufacture of semiconductor components or devices prior to anytype of tuning or trimming as discussed herein. Similarly, it is to beunderstood herein that the expression “laid down base conductive path”(i.e. initial conductive path) in relation to a device or component is areference to a conductive path or region having been created with aninitial (i.e. non-infinite) impedance (e.g. non-infinite resistance)prior to any type of tuning or trimming as discussed herein.

Thus, for example, in accordance with the present invention, in relationto the expression “laid down base conductive path” a semi-conductorcomponent or device. before any trimming or tuning as described herein,may already be capable of acting as an electrical conductor having aninitial (non-infinite) impedance which may already be near the soughtafter value, i.e. the initial value is higher than the desired endvalue. In other words, it is further to be understood herein that atunable semiconductor component or, device and the like in accordancewith the present invention is a semiconductor component, device etcalready having a gross impedance obtained as a result of the initialmanufacturing process of laying down appropriate layers, substrates etc.This means that the semiconductor construct, device or component has ameasurable impedance which may be tested even before being subjected toany type of trimming or tuning as described herein i.e. thesemiconductor device or component may have, as mentioned above, a “baseconductive path” even before the application of any laser tuningprocess, i.e. it has a base conductive path which is a “laid down baseconductive path”.

In accordance with the present invention it is further to be understoodherein that the reference to a “focused heating source” or the like, isa reference to any type of heating source of any kind whatsoever (e.g. alaser) whereby one is able to direct, concentrate or apply energy to apredetermined target area (i.e. a target area as described herein) so asto heat the target area for the purpose of altering the dopant profilethereof.

Turning now to the tuning of a device of the present invention, aconductive bridge may be obtained by the application of a bridging cyclecomprising one or more laser or heat pulses applied over a (complete)bridge area which may comprise a respective portion of the first linkmember, of the gap region, of the current mask member or region disposedin the gap region and of the second link member. Thus a bridging cyclemay comprise applying a heating/cooling treatment to such a bridge area(i.e. complete bridge area), the heating/cooling treatment comprising

directing a focused heating source to melt the bridging area either as awhole or in increments thereof so as to thereby alter the dopant profileof the melted bridging area and

allowing said melted bridging area to solidify with an altered dopantprofile so as to form thereby said discrete conductive bridge. Ifdesired or needed, a bridging cycle may comprise applying, after aninitial heating/cooling treatment, one or more additionalheating/cooling treatments to the same heat treated bridging area orportion thereof so as to form thereby said discrete conductive bridge,i.e. a bridging cycle may comprise applying two or more of theheating/cooling treatments to the same bridging area.

More details with respect to the bridging cycles may for example befound in above mentioned U.S. Pat. No. 6,329,272 or U.S. Pat. No.6,890,802. As mentioned above, in these patents a conductive bridge orlink may be obtained by application of a single heat (e.g. laser) pulse;alternatively a conductive link may by obtained by the application of aseries of pulses such as for example as described in above mentionedU.S. Pat. No. 6,329,272.

In accordance with the present invention a conductive bridge may, if sodesired or appropriate be formed by a controlled diffusion, i.e. it maybe formed by a careful, calculated and measured application of focusedenergy being applied to the integrated semiconductor device, which mayresult in a controlled and/or determinable quantity of dopants beingdiffused from one area to an adjacent area having a lower dopantconcentration.

Alternatively, in accordance with the present invention, a conductivebridge may. for example, advantageously, be formed from the applicationof an indiscriminate pulse from a high powered laser (i.e. a blast ofenergy); the pulse spanning across the gap region over a part of each ofthe link portions and being applied so as to a provide (under pre-givenconditions) a degree of diffusion which may vary from the minimum amountof diffusion (necessary to provide a conductive bridge) to a maximumamount of diffusion which likewise results in a desired conductivebridge.

In accordance with the present invention, semiconductor components ordevices may be tuned, which expression (tuned or tuning) is understoodto mean that the impedance of the integrated semiconductor device may bemodified, adjusted, changed, (i.e. decreased). It is further understoodthat fine tuning of an integrated semiconductor device is understood tomean that the impedance, once it has been grossly obtained (i.e. by theinitial manufacturing process of laying down appropriate layers,substrates etc.), may be finely tuned (i.e. finely adjusted, or withhigh precision). Fine tuning may involve a single step or a distinctseries of steps.

In accordance with the present invention, the tuning of an integratedsemiconductor device may be accomplished iteratively, i.e. through theuse of an iteration technique or method such as describe for example inabove mentioned U.S. Pat. No. 6,329,272 or U.S. Pat. No. 6,890,802.Thus, iteratively or iteration technique is to be understood to mean aprocess, action or procedure in which repetition of a sequence ofoperations yields results which are successively closer to a desiredresult. Therefore, the objectives of a particular embodiment of thepresent invention may be accomplished through the use of an iterationtechnique, by which the successive application of heat (i.e. one or morepulses) from a focused heating source to different areas, mayprogressively yield an impedance profile which is progressively closerto the required or desired profile across a given integratedsemiconductor device.

In accordance with a general aspect of the present invention, an(integrated) semiconductor device may comprise a number of components.Included among these components may be areas which may be doped withdopants, such as for example, n-type or p-type dopants. The dopantconcentration of various areas of a device may vary according to theiruse and application. There may be, for example, areas of a given dopantconcentration, and adjacent thereto there may be areas of lower dopantconcentration. In accordance with an embodiment, there may therefore bea pair of opposed first areas of a predetermined or selected dopantconcentration (e.g. high p-type dopant concentration), and an adjacentintermediate second or gap region or area of a (relative) lower dopantconcentration (e.g. low n-type dopant concentration). The gap region orarea may be interrupted by a mask region or area of the same dopant typeas the intermediate gap area. The mask region or area may have a (e.g.n-type) dopant concentration which is higher than that of the gap regionor area but which is lower than that of the first opposed region orareas (e.g. any p-type dopant present in the mask region or area due toimperfect lithographic masking being in a more diluted state relative tothe n-type dopant such that the mask region or area may be considered tohave a n-type dopant composition). As may be understood, the purposesthereof, the difference in the dopant concentration between areas may besufficient such that the physical and electrical properties of each ofthe areas may be different, i.e. for example, one may conduct electricalcurrent, while the other may not, or their relative capability toconduct electrical current may be different.

By way of example, in accordance with the present invention, in order tomodify the relative dopant concentration difference between first dopedareas and a current mask interrupted intermediate second doped area, thefollowing iterative steps may be effected: namely, a focused heatingsource may be targeted at a selected region or area. which selectedregion or area may comprise therein at least a portion of a first dopedregion or area, at least a portion of the intermediate second dopedregion or area, and at least a potion of a current masked region or areai.e. the selected region or area may straddle the boundary between afirst and second doped region or area as well as a current mask dopedregion or area. As may be understood, the selected area may be generallyround, and may or may not evenly straddle the boundaries between thefirst and the second doped regions.

More particularly, in accordance with of the present invention, anintegrated semiconductor device may be provided in any suitable (known)manner wherein the composition of the various regions has beenconfigured such that the device comprises, two conductivelyinterconnected areas or regions of relatively high (e.g. p-type) dopantconcentration which are spaced apart by a gap area or region of arelatively lower (e.g. n-type) dopant concentration, the gap area orregion being interrupted by a current mask region or area of relativelyhigh (e.g. n-type) dopant concentration. The current mask region may forexample, be considered to be of an n-type composition notwithstandingthe presence therein of p-type dopant provided that the concentration ofp-type dopant is lower than that of n-type dopant. Thus the gap regionor area of lower dopant concentration may act as an insulator, betweenthe two first areas of higher dopant concentration and the current maskregion as an additional current barrier interrupting the gap area foroffsetting current leakage across the gap area. The dopant type and/orconcentration thereof of the gap area and current mask area may be of atype and/or concentration such that no or at least essentially noelectrical current may flow directly across the gap and mask regionswithout the presence of a bridge area or element produced by a heatcycle as described herein.

It is understood that for some electrical current to pass through abridge area of lower dopant concentration disposed between two areas ofhigher dopant concentration, it is necessary to arrange that the type ofdopant in the higher dopant areas be identical, i.e. either all of ntype, or all of p type. In accordance with this aspect of the presentinvention a laser trimming method may be used to modify the dopantconcentration of a part of the gap region thereof, therefore decreasingthe pre-existing impedance of any part of an integrated semiconductordevice. In other words the use of the method of the present embodimentmay allow for the impedance of an integrated semiconductor device to bemodified such that some electrical current (i.e. as opposed to noelectrical current) may be able to flow across a conductive bridgespanning a gap region.

The type of dopant (or dopants) used in a lightly (i.e lower) dopedregion may. however, not be the same as the type of dopant use in theheavily (i.e. higher) doped regions. For example, if the heavily dopedregion uses a p type dopant, the lightly doped region is to be of ntype, and vice versa. It is understood that in this case, the amount ofdopant to be diffused from the area (or areas) of higher dopantconcentration into the area of lower dopant concentration may need to behigh enough to counter the presence of the different type of dopantpresent in the lightly doped area, such that current may flow throughsaid lightly doped area.

The level of concentration of the dopants in the areas of high and lowconcentration may vary significantly. For example, the dopantconcentration may vary between 10¹² to 10²⁰ atoms per cm³ The range ofdopant concentration for a lightly doped area may, for example, bebetween 10¹² to 10¹⁶ atoms per cm³ while the dopant concentration for anarea of high dopant concentration may, for example, be between 10¹⁶ to10²⁰ atoms per cm³. In any event, the dopant concentration(s) may bethose (normally) encountered in industry, i.e. they may, be higher orlower than mentioned herein above.

It is understood that the terms lightly doped region and heavily dopedregion are not meant to exclude a first doped region which dopantconcentration is only slightly higher than a second doped region(depending on dopant type). The appropriate or suitable dopantcomponents which may be used in accordance with the present inventionmay be selected as required from the group comprising boron, phosphorus,aluminium, antimony, arsenic, gallium, indium, lithium, thallium andbismuth. The dopants may be doped in a substrate comprising a materialselected from the group comprising silicon, gallium arsenide,silicon-germanium, as well as any suitable compounds selected fromcolumns III-V and II-VI of the periodic table, and compounds having aIV-IV alloy.

Although the present invention is discussed herein by way of example inrelation to laser based heat sources, the “focused heating source” whichmay be used in accordance with the present invention may, as mentionedabove, be any (e.g. known) source suitable for the purposes herein; itmay for example be a suitable configured device using an electron beam(e.g. the heat source may be selected from a group comprising a laserand an electron beam). Further, the energy of the heating pulses of saidfocused heating source may be low enough to avoid damaging theintegrated semiconductor device.

Although the current mask aspect of the present invention will bedescribed below in particular with respect to a device comprising havinga U-like shaped laid down base conductive path the conductive path mayhave any other shape such as described for example in U.S. Pat. No.6,890,802.

Example embodiments of the present invention are illustrated in thedrawings wherein;

FIG. 1 illustrates schematically an example of a prior art tunablesemiconductor component or device, wherein the first conductive regiondefines a laid down base conductive path which is disposed in the formof a conductive crimp element having a U-like shape configuration orpattern;

FIG. 1 a illustrates schematically a (dopant) masked cross-section ofthe undoped substrate used to make the semiconductor component or deviceshown in FIG. 1 by any (known) doping technique (e.g. ion implantation);

FIG. 1 b illustrates schematically a (dopant) masked cross-section ofthe doped substrate used to make the semiconductor component or deviceshown in FIG. 1;

FIG. 1 c illustrates schematically a cross-section along 1 c-1 c of thedevice shown in FIG. 1 (i.e. wherein the (dopant) mask has beenremoved);

FIG. 2 illustrates schematically an example of a tunable semiconductorcomponent or device in accordance with the present invention, whereinthe first conductive region defines a laid down base conductive pathwhich is disposed in the form of a conductive crimp element having aU-like shape configuration or pattern associated with an example currentmask region or member of the present invention;

FIG. 2 a illustrates schematically illustrates schematically a (dopant)masked cross-section of the doped substrate as shown in FIG. 1 c used tomake the semiconductor component or device shown in FIG. 2 by any(known) doping technique (e.g. ion implantation);

FIG. 2 b illustrates schematically a (dopant) masked cross-section ofthe doped substrate comprising a current mask region used to make thesemiconductor component or device shown in FIG. 2;

FIG. 3 illustrates schematically a cross-section along 3-3 of the deviceshown in FIG. 2 (i.e. wherein the (dopant) mask for making the currentmask region has been removed);

FIG. 3 a illustrates schematically the cross-section shown in FIG. 3 butwherein the device has one or more additional laser transparentoverlayers;

FIG. 4 illustrates schematically another example of a tunablesemiconductor component or device in accordance with the presentinvention, wherein the first conductive region defines a laid down baseconductive path which is disposed in the form of a conductive crimpelement having a U-like shape configuration or pattern associated withan example current mask member of the present invention connected to orcontiguous with the conductive path;

FIG. 5 illustrates schematically a further example of a tunablesemiconductor component or device in accordance with the presentinvention, wherein the first conductive region defines a laid down baseconductive path which is disposed in the form of a conductive crimpelement having a U-like shape configuration or pattern associated withan example current mask member of the present invention disposed towardsthe second link member.

FIG. 6 illustrates schematically the tunable semiconductor component ordevice shown in FIG. 2 wherein the gap region 5 is spanned by aconductive bridge;

FIG. 7 illustrates schematically another a tunable semiconductorcomponent or device in accordance with the present invention, whereinthe first conductive region defines a laid down base conductive path inthe form of a plurality of conductive crimp elements each having aU-like shape or pattern, each crimp element being associated with arespective current mask region or member;

FIG. 8 illustrates schematically an example embodiment of a tunablesemiconductor component or device in accordance with the presentinvention, wherein the semiconductor device or component may beconfigured to custom define by heat trimming a fractional amount ofcurrent that may flow through a predetermined electronic circuit:

FIG. 9 a illustrates an electric schematic of the untuned semiconductorcomponent or device of FIG. 8 further comprising a metallic bridgeelement;

FIG. 9 b illustrates an electric schematic of the semiconductorcomponent or device of FIG. 8 tuned in accordance with the presentinvention and wherein the metallic bridge element has been severed;

FIG. 10 illustrates schematically another example embodiment of atunable semiconductor component or device analogous to that shown inFIG. 8; and

FIG. 11 illustrates schematically another embodiment of a tunablesemiconductor component or device analogous to that shown in FIG. 8which includes a current mask member.

FIG. 1 illustrates a prior art tunable semiconductor component or deviceas shown in FIG. 1 of U.S. Pat. No. 6,890,802. FIGS. 2 to 7 on the otherhand illustrate example embodiments of a tunable semiconductor componentor device in accordance with the present invention provided withrespective current mask regions or members. The same reference numeralswill be used for each of the FIGS. 1 to 7 to denote common or analogouselements.

For each of FIGS. 1 to 7 the tunable semiconductor component or deviceis generally designated by the reference numeral 1. The device 1 in eachcase may comprise various layers or regions, for example, a generalnon-conductive substrate or region 2, and a conductive layer or region 2a which is contiguous with the underlying general substrate or region 2.

The region 2 a as illustrated in FIGS. 1 to 6 is shown as having asingle crimp element, the crimp element having a first link member orportion 3 and juxtaposed therewith a second link member or portion 4. Onthe other hand, the embodiment shown in FIG. 7 is shown as having aplurality of crimp elements (i.e. three crimp elements) and as having aplurality of first and second link members 3 and 4; as may beappreciated the link members 3 and 4 of the central crimp element aredefined by a link member of an adjacent crimp element and so on.

Referring in particular to FIGS. 1, 2, 4, 5, 6 and 7 the devicesillustrated also have a spacing link member or portion 4 a which linksthe first and second link members or portions together. The first andsecond link members 3 and 4 are spaced apart by gap region 5 which isdefined by the general region 2. The gap region 5 may, as shall bediscussed in more detail with respect to FIG. 6, be subsequently spannedby one or more heat produced conductive bridges due to (laser) trimming.The devices also have contact or connector members 8 and 9 forelectrically connecting the region 2 a to other devices, i.e. electricalcurrent is at least initially able to pass through the entire region 2 abetween these contact members.

The general substrate or region 2 as mentioned above comprises the gapregion 5 which is disposed intermediate the first and second linkmembers 3 and 4 of the region 2 a.

Turning to FIG. 1, the gap region 5 for this prior art device is shownuninterrupted by any other members and as having a spacing as seen fromthe arrow 5 a (e.g. from 0.1 to 5.0 microns) between the first andsecond link members 3 and 4.

FIGS. 1 a, 1 b and 1 c show in progressive illustrative schematicfashion the laying down of the region 2 a (i.e. by doping of unmaskedportions of substrate 2) and in particular the laying down of the firstand second link members 3 and 4 of the region 2 a. The substrate 2 mayfor example be pre-configured to comprise an n-type dopant compositionof light n-type dopant concentration. The formation of the region 2 amay be accomplished by the application of a mask member to the substrate2 by any known (optical) lithographic technique so as to leave thedesired areas (i.e. pattern) of the substrate 2 uncovered by the maskmember. The uncovered area(s) of the substrate 2 may then be doped asdesired by any (known) doping technique (i.e. by diffusion, ionimplantation, etc.) to obtain the first conductive region 2 a.

Thus as seen in FIG. 1 a the substrate or region 2 is covered by a maskmember; for discussion purposes the mask member (as seen incross-section in FIGS. 1 a and 1 b) may be considered as having threeparts designated generally by the reference designations 3 a, 4 a and 5b. As may be appreciated the mask part 5 b covers the region of thesubstrate 2 which is intended to define the gap region 5. The maskedparts 3 a and 4 a as seen are spaced apart from the part 5 b so as toleave unmasked areas of the substrate 2 which will doped to provide thefirst and second link members 3 and 4 of the region 2 a (see FIGS. 1 band 1 c).

As shown schematically in FIG. 1 a the arrows 5 c illustrate theapplication of the desired dopant (e.g. a p-type dopant) to the exposedparts of the substrate so as to obtain first and second link members 3and 4 (e.g. of high p-type dopant concentration).

Although the part 5 b covers the gap region 5, the masking may beimperfect such that an undesired (thin) hybrid layer or region 5 c maybe formed having a p-type dopant character. As shown the hybrid layer orregion 5 c spans the distance between the first and second link members3 and 4. However the hybrid layer or region 5 c may not span suchdistance but comprise one or more hybrid region(s) which is/arecontiguous with only one of the link members or even be non-contiguouswith both of the link members; the hybrid region(s) may also comprise aplurality of non contiguous hybrid regions. In any event, depending onthe materials of the mask member, the thickness of the mask member, thedoping technique, the spacing 5 a between the first and second linkmembers 3 and 4, the applied voltage of use, etc., an electrical currentmay be able to jump or short circuit across the gap region 5 between thefirst and second link members 3 and 4 (e.g. as illustrated by arrow 5 a)due to the presence of the undesired hybrid layer or region 5 c.

Turning to FIGS. 2 to 7, each of the gap regions 5, of the devices inaccordance with the present invention, is interrupted by a respectivecurrent mask member or region 6, 7 a or 7 b which are also contiguouswith the underlying general substrate or region 2.

The current mask member or region 6 (see FIGS. 2 and 7), as shown, isnot connected to the spacing link member or portion 4 a and is more orless centrally disposed in the gap region 5 so as to be spaced apartfrom the first and second link members 3 and 4 of the region 2 a (seealso FIG. 3). The current mask member or region 6 is also of a lengthwhich is shorter than that of the first and second link members 3 and 4.

The current mask member or region 7 a (see FIGS. 4 and 7), as shown, isconnected to or contiguous with the spacing link member or portion 4 a.The current mask member or region 7 a is shown as being more or lesscentrally disposed in the gap region 5 whereas the current mask member 7b (FIG. 5) is shown as being disposed towards the second link member 4.In any case, the current mask members or regions 7 a and 7 b are spacedapart from the first and second link members 3 and 4 of the region 2 a.The current mask member or region 7 a is also of a length which is moreor less equal to that of the first and second link members 3 and 4. Thecurrent mask member or region 7 b is of a length which is shorter thanthat of the first and second link members 3 and 4.

The spacing between a current mask member or region and the first andsecond link members 3 and 4 of the region 2 a may take on any suitableor desired value keeping in mind the function of the current mask memberor region, namely to offset possible leakage of electrical currentacross the gap region 5 between the first link member 3 and the secondlink member 4. Referring to FIG. 2 the current mask area or region 6 maybe a distance (arrows 5 d and 5 e), from either of the above mentionedlink members, of 5.0 microns or less (e.g. from 0.1 to 3.0 microns) andin particular a distance of 0.8 microns or less (e.g. from 0.2 to 0.8microns). The current mask area or region 6 may take on any desired ornecessary shape and/or thickness keeping in mind its function.

The gap region 5 may have a width dimension which, in light of theinitial fabrication process, may for example, vary from the minimumdesired or necessary size (e.g. from 0.2 to 0.8 microns), up to about 10microns or more, keeping the above in mind; the gap width may forexample vary in accordance with the type of heat pulse treatment to beused; e.g. if a single pulse is to be used then as small a width aspossible may be in order; if a series of heat pulses is to be used thena large width may be contemplated. In accordance with the presentinvention the gap width will also vary in accordance with theconfiguration and disposition of a current mask member disposed therein.

It is to be understood herein of course that the current mask members orregions 6, 7 a and 7 b are given for illustrative purposes only. Acurrent mask member may take on any other configuration or dispositionkeeping in mind its function, namely to offset leakage of electricalcurrent across the gap region between the first link member 3 and thesecond link member 4.

Turning back to FIGS. 2 a, 2 b and 3, these figures show in progressiveillustrative schematic fashion the laying down of the current maskregion 6 (i.e. by doping of unmasked portions of substrate 2) on asubstrate previously provided with the first and second link members 3and 4 of the region 2 a; for illustrative purposes the hybrid layer orregion 5 c is not shown in FIGS. 2 a, 2 b and 3. The formation of thecurrent mask region 6 may also be accomplished by the application of amask member to the substrate 2 by any known (optical) lithographictechnique so as to leave the desired areas (i.e. pattern) of thesubstrate 2 uncovered by the mask member. The uncovered area(s) of thesubstrate 2 may then be doped as desired by any (known) doping technique(i.e. by diffusion, ion implantation, etc.) to obtain the current maskregion 6.

Thus as seen in FIG. 2 a the substrate or region 2 is covered by a maskmember. for discussion purposes the mask member (as seen incross-section in FIGS. 2 a and 2 b) may be considered as having twoparts designated generally by the reference designations 6 a and 6 b. Asmay be appreciated the masked parts 6 a and 6 b as seen are spaced apartso as to leave an unmasked area of the substrate 2 which may be doped toprovide the current mask region 6 which interrupts the gap region 5.

As shown schematically in FIG. 2 a the arrows 6 c illustrate theapplication of the desired dopant (e.g. a n-type dopant) to the exposedpart of the substrate 2 so as to obtain the current mask region 6 (e.g.a region 6 of high n-type dopant concentration relative to the rest ofthe substrate 2 which may have a dopant composition of n-type of lightor low n-type dopant concentration). Thus, for example, if the linkmembers 3 and 4 have a dopant composition of p-type, sufficient n-typedopant may be applied to the exposed substrate between the mask parts 6a and 6 b so as to ensure that the region 6 has a dopant compositionwhich is of n-type character sufficient such that said current maskregion 6 interrupts said gap region 5 for offsetting possible leakage ofelectrical current across the gap region between the first link memberand the second link member. In effect the doping to get the region 6 issuch as to offset or overcome any p-type character that the substratemay have previously had due to the presence of a p-type hybrid layer 5c.

FIGS. 2 a and 2 b show the formation of the current mask region 6 onto asubstrate previously provided with the first link member and the secondlink member. Alternatively the current mask region 6 may initially beprovided onto a substrate, followed by the laying down of the first linkmember 3 and the second link member 4. In this latter case, for example,an n-type character of the current mask region 6 may be maintained bythe application of a sufficient concentration of n-type dopant to theregion 6 such that any leakage of p-type dopant across the mask membercovering the gap region 5 will not overcome the n-type character of thecurrent mask region 6.

It is to be understood of course that the dopant character of thevarious regions may be reversed, i.e. the region 2 a may be of n-typedopant character whereas the other regions may be of p-type dopantcharacter.

Although the current mask region has been discussed above in relation tothe presence of a hybrid layer or region, it is to be understood thatsuch a current mask region may be laid down even in the absence of sucha hybrid layer or region, i.e. as a back-up non-conductive region foroffsetting possible current leakage due to factors other than thepresence of such hybrid layer or region (e.g. spacing requirements). Inany event, the presence of a current mask region may allow for lessstringent masking conditions to, be used, than may otherwise need to beused, in order to achieve the desired non-conductive effect.

As mentioned the region 2 a may be a heavily doped region, i.e. suchthat region 2 a is an electrically conductive region having a heatmodifiable dopant profile. As mentioned above, the expression “heatmodifiable dopant profile” characterizes a region or area (as the casemay be) as being one which may, on the application of a suitable heatsource, be melted such that dopant may migrate or diffuse there throughso as to alter the dopant profile thereof and which altered dopantprofile may be maintained on solidification of the melted area.

On the other hand the gap region 5 as well as current mask member orregion may for their part also have a heat modifiable electricallyconductive dopant profile which is different from that of the region 2a, keeping in mind their function, namely to offset or inhibit possibleleakage of electrical current across the gap region between the firstlink member 3 and the second link member 4. Thus, for example, thecurrent mask member 6 shown in FIG. 2 may have a heat modifiableelectrically conductive dopant profile different from that of the region2 a as well as the gap region 5. Similarly, the current mask members orregions 7 a and 7 b contiguous with the region 2 a as shown in FIGS. 4and 5 may have a heat modifiable electrically conductive dopant profilewhich is the different from that of the region 2 a.

In any event the region 2 including the gap region 5 and the currentmask region 6 have a dopant profile such that for the purposes hereinregion 2 is a relatively electrically non-conductive region in relationto the region 2 a and in particular relative to the first and secondlink portions 3 and 4 thereof. Thus, relative to the region 2 a, theregion 2 including the gap region 5 and the current mask region 6 mayeach be a doped region of lower dopant concentration then the region 2a. The region 2 as in the case of the region 2 a, at least in the gapregion has a heat modifiable dopant profile.

The regions 2 and 2 a as well as the current mask member or region mayeach comprise suitable or appropriate semiconductor materials such asmentioned hereinabove. The substrate may for example be selected fromsubstrate materials such as silicon, germanium, gallium arsenide,silicon-germanium and other suitable semiconductor materials.

As may be understood herein, a heavily doped region 2 a may be heavilydoped with either n or p type dopants in sufficient concentrations, andof a required or desired profile such that the heavily doped region iselectrically conductive. For example, the dopants may be phosphorous,and may be of a concentration of the order of between 10¹⁶ to 10²⁰ atomsper cm³. The thickness of the heavily doped regions may for example beof 0.25 micrometers, but may be greater or lesser in accordance with therequirements of a given manufacturing process. Further, theconfiguration and disposition of such a heavily doped region may also bein accordance with the requirements of a given manufacturing process.

If a region is lightly doped or of lower relative dopant concentration,it is doped with a different dopant type than that present in anadjacent heavily doped region. A lightly doped gap region 5 may bedisposed to be adjacent to and abutting the heavily doped first andsecond link members 3 and 4 as well as a relatively higher doped currentmask member or region.

The type and concentration level of dopants in lightly and heavily dopedregions is in any event to be selected such that, prior to, as well asafter the application of the heat trimming method steps, electricalcurrent flow directly between heavily doped members 3 and 4 across thegap region 5 and across the current mask member, is inhibited. In otherwords. such cross over current flow is to be favoured by beingchannelled over a discrete conductive bridge connecting the first linkmember to the second link member, such conductive bridge spanning thegap region as well as the current mask member and having been created byany suitable (know) heat trimming (e.g. laser trimming) technique(s).Suitable trimming technique(s) which may be applied to a device of thepresent invention for the formation of such a conductive bridge(s) areoutlined in detail in the above mentioned U.S. Pat. No. 6,329,272 andU.S. Pat. No. 6,890,802. Referring to FIG. 6, this figure illustratesand example conductive bridge 20 shown in dotted outline spanning thegap region 5 as well as the current mask member 6.

Referring to FIG. 3 a, this figure illustrates an example embodiment ofa semiconductor component or device of the present invention which maycomprise one or more overlaying layers (one of which is shown and isdesignated with the reference numeral 22) which are transparent tosuitable heat source e.g. laser (i.e. light) transparent layer(s). Thetransparent layer(s) may comprise an oxide layer(s) e.g. a layer ofsilicon dioxide SiO₂. The transparent layer(s) are such as to allow heattrimming of the underlying device structure.

Turning to FIG. 8, this figure illustrates an example embodiment of atuneable semiconductor component or device in accordance with thepresent invention, wherein the semiconductor device or component may beconfigured to custom define by heat trimming a fractional amount ofcurrent that may flow through a predetermined electronic circuit. Thesemiconductor component comprises a first conductive region 30 defininga first laid down base conductive path, and a second conductive region32 defining a second laid down base conductive path. Both the firstregion 30 and the second region 32 of this embodiment are doped regionshaving a heat modifiable dopant profile which may be of the same ordifferent dopant composition. The semiconductor component or devicefurther comprises a third region 34 contiguous with the first and secondregions, i.e. regions 30 and 32 are laid down on the underlying region34 in similar fashion as for the devices as seen from FIGS. 1 and 2.This third region 34 is a doped region having a dopant profile renderingthe third region non-conductive relative to the first and second regions(see above). The first and second regions 30 and 32 are disposed injuxtaposition such that the first and second regions are separated by agap region 36 defined by said third region. The third region has a heatmodifiable dopant profile, at least with respect to said gap region. Thefirst region has respective contact means 40 and 42 and the secondregion has respective contact means 44; the respecteive conacte meansare for electrically connecting the first and second regionsrespectively to one or more other electrical elements (the electricalelements are designated generally by the reference numerals 46, 48 and50); the other electrical elements may take on any desired necessaryform or configuration and are connected to the contact means by suitableelectrically conductive lines. The second conductive region 32 as seenin FIG. 8 comprises a T-like shaped member having a head element oflength 54 and a tail element 56 projecting from the head element. saidtail element 56 comprising said contact means 44, said head elementbeing disposed in juxtaposition with said first region so as to beseparated by said gap region 36 having a span distance 36 a similar tothat of distance 5 a of FIG. 1.

The first, second and third regions 30, 32 and 34 may be doped asreferred to above with respect to the devices shown in FIGS. 2 to 7keeping in mind the purpose of a device as shown in FIG. 8 is to allowfor the custom definition of a conductive bridge by heat trimming acrossthe gap such that the device may provide a fractional amount of currentflow through the predetermined electronic circuit 50. In other wordswhen a conductive bridge 60 such as shown in dotted outline in FIG. 8 isformed for example by laser trimming as referred to above, theelectrical result is a resistance or impedance circuit as shown in FIG.9 b. As desired or necessary more than one such conductive bridge 60 maybe formed to obtain a desired or necessary current division.

As shown in FIGS. 8 and 9 a the first and second regions 30 and 32 mayinitially be interconnected by a metallic bridge element 70 set in placein any suitable (e.g. lithographic) manner; the bridge element 70 may beused to test the electrical integrity of the device prior to heattrimming. Once the heat trimming is to be done the bridge element 70 maybe cut or severed for example by use of a suitable laser.

Referring to FIGS. 9 a and 9 b once the metallic bridge element 70 iscut and prior to heat trimming the current I_(T) flows between contactmeans 40 and 42. After the formation of the desired or necessaryconductive bridge(s) the current may be divided as shown in FIG. 9 bsuch that I_(T)=I₁+I₂.

For FIGS. 10 and 11 the same reference numerals will be used todesignate common elements.

FIG. 10 illustrates a modified alternate embodiment of tuneablesemiconductor component or device shown in FIG. 8 wherein the secondregion 32 a has an L-like shape rather than a T-like shape.

FIG. 11 illustrates a further modified embodiment of tuneablesemiconductor component or device shown 1 FIG. 8 wherein the device isprovided with a discrete current mask member or region 90 having thecharacteristics of a current mask member or region as described abovewith respect to FIGS. 2 to 7. The mask region is spaced apart from theregions 30 and 32 by the distances designated by the arrows 36 c and 36b which may have values as mentioned above in relation to the arrows 5 dand 5 e of FIG. 2.

1. An impedance tunable semiconductor component, said semiconductorcomponent comprising a first conductive region, and a second region saidfirst conductive region comprising a first type dopant composition saidsecond region comprising a second type dopant composition said firstconductive region and said second region being contiguous, said firstconductive region defining a laid down base conductive path, said secondtype dopant composition having a dopant profile configured to rendersaid second type dopant composition non-conductive relative to saidfirst type dopant composition said first conductive region comprising afirst link member and a second link member, said first and second linkmembers being disposed in juxtaposition such that said first and secondlink members are separated by a gap region defined by said secondregion, said first conductive region having a heat modifiable dopantprofile, said second region having a heat modifiable dopant profile, atleast with respect to said gap region, characterised in that saidsemiconductor component further comprises a laid down current maskregion disposed between and spaced apart from said first link member andsaid second link member, said current mask region having a heatmodifiable dopant profile, and wherein said current mask regioncomprises a third type dopant composition different from that of saidfirst and second type dopant compositions such that said current maskregion interrupts said gap region for offsetting leakage of electricalcurrent across the gap region between the first link member and thesecond link member.
 2. An impedance tuneable semiconductor component,said semiconductor component comprising a first conductive regiondefining a first discrete laid down base path for electrical conduction,said first region being a doped region having a heat modifiable dopantprofile. a second conductive region defining a second discrete laid downbase path for electrical conduction, said second region being a dopedregion having a heat modifiable dopant profile and a third regioncontiguous with the first and second regions and being a doped regionhaving a dopant profile rendering said third region electricallynon-conductive relative to said first and second regions, at least apotion of said second discrete laid down base path being disposed injuxtaposition with said first discrete laid down base path such thatsaid first and second discrete laid down base paths are therebyseparated by a gap region defined by said third region, said thirdregion having a heat modifiable dopant profile, at least with respect tosaid gap region, said first conductive region having a pair ofelectrical contact means for electrically connecting the firstconductive region to two or more electrical elements, said secondconductive region having an electrical contact means for electricallyconnecting the second conductive region to one or more electricalelements.
 3. An impedance tuneable semiconductor component as defined inclaim 2 wherein said second discrete laid down base path comprises afirst element disposed transverse to a second element projecting fromthe first element, said second element comprising said contact means ofsaid second conductive region, said first element being disposed injuxtaposition with said first discrete laid down base path so as to beseparated therefrom by said gap region.
 4. An impedance tuneablesemiconductor component as defined in claim 3 wherein said seconddiscrete laid down base path comprises a T-like shaped member having ahead element and a tail element projecting from the head element, saidtail element comprising said contact means of said second conductiveregion, said head element being disposed in juxtaposition with saidfirst discrete laid down base path so as to be separated therefrom bysaid gap region.
 5. An impedance tuneable semiconductor component asdefined in claim 3 wherein said second discrete laid down base pathcomprises an L-like shaped member having a foot element and a legelement projecting from the foot element, said foot element comprisingsaid contact means of said second conductive region, said foot elementbeing disposed in juxtaposition with said first discrete laid down basepath so as to be separated therefrom by said gap region.
 6. An impedancetuneable semiconductor component as defined in claim 2 further includinga laid down metallic bridge element and wherein said first and secondconductive regions are electrically interconnected by said metallicbridge element, said metallic bridge element being severable by afocused heating source.
 7. An impedance tuneable semiconductor componentas defined in claim 2 said semiconductor component further comprises alaid down current mask region interposed in said gap region, saidcurrent mask region having a heat modifiable dopant profile, and whereinsaid current mask region comprises a dopant profile different from thatof said first and second type dopant compositions such that said currentmask region interrupts said gap region for offsetting leakage ofelectrical current across the gap region between said first and secondconductive regions.